Clinical Research
Disinfecting Effects of Rotary Instrumentation with Either 2.5% Sodium Hypochlorite or 2% Chlorhexidine as the Main Irrigant: A Randomized Clinical Study

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Abstract

Introduction

This randomized clinical study compared the antibacterial effects of irrigation with either 2.5% sodium hypochlorite (NaOCl) or 2% chlorhexidine (CHX) during the preparation of infected root canals with rotary nickel-titanium instruments.

Methods

The root canals of 50 single-rooted teeth with apical periodontitis were prepared by using BioRaCe rotary instruments (FKG Dentaire, La Chaux-de-Fonds, Switzerland) and irrigation with either 2.5% NaOCl (n = 25) or 2% CHX (n = 25). Samples were taken from the canal at baseline (S1) and after (S2) chemomechanical preparation. DNA was extracted from the clinical samples, and the reduction of the levels of total bacteria and streptococci was evaluated by means of a 16S ribosomal RNA gene-based quantitative polymerase chain reaction assay.

Results

All S1 samples were positive for the presence of bacteria. After chemomechanical preparation using either 2.5% NaOCl or 2% CHX, 44% and 40% of the root canals still had detectable bacteria, respectively. As for total bacterial counts, a mean number of 3.7 × 105 bacterial cell equivalents was present in S1 samples from the NaOCl group, with a substantial reduction in S2 to a mean of 5.49 × 102 cell equivalents (P < .001). In the CHX group, a mean bacterial load of 8.77 × 104 cell equivalents occurred in S1, with a significant reduction in S2 to a mean of 2.81 × 103 cells (P < .001). The differences in both the presence/absence and quantitative data were not statistically significant (P > .05). Both irrigation protocols were highly effective in reducing the levels of Streptococcus species (P < .001).

Conclusions

No significant difference was observed for the clinical antibacterial effectiveness of rotary preparation using either 2.5% NaOCl or 2% CHX as the main irrigant.

Section snippets

Subjects

The study population consisted of subjects attending the endodontic clinic at the School of Dentistry, Estácio de Sá University, Rio de Janeiro, RJ, Brazil, for evaluation and treatment of apical periodontitis from March 2009 to December 2010. Only teeth with a single root and a single canal and presenting with carious lesions, necrotic pulps confirmed by pulp tests, and clinical and radiographic evidence of asymptomatic apical periodontitis were included in the study. Reasons for exclusion

Results

Of the 50 individuals included in the study, 27 were male and 23 female, with a mean age of 29 years (range, 13–52 years). All of them reported no significant systemic condition. Each individual contributed 1 tooth.

Bacteria were detected in all samples taken before treatment as revealed by qPCR with universal 16S rRNA gene-based primers. After chemomechanical preparation with rotary instruments and irrigation with either 2.5% NaOCl or 2% CHX, 44% and 40% of the root canals still had detectable

Discussion

The present culture-independent molecular microbiology study was undertaken to evaluate the antibacterial effects of chemomechanical preparation using rotary instrumentation with either 2.5% NaOCl or 2% CHX as the main irrigant in teeth with primary apical periodontitis. Treatment procedures using either solution promoted a substantial reduction in bacterial counts. This is in consonance with many other quantitative culture and molecular analyses of the antibacterial effects of

Acknowledgments

Supported by grants from Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazilian Governmental Institutions.

The authors deny any conflicts of interest related to this study.

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